The problem, moreso, with fixed wing is when the Scillies gets fog.
Fog clears by the sun breaking through, warming the land, and the heat from the land clearing the fog. The trouble with the Scillies is that there's so little land that, by perhaps lunchtime, they might have just achieved perhaps 1500M visibility but the, fixed wing, approaches are still clagged up thus missed approaches, diversions, are moreso than at regular airfields.